The bioactive components of microbial origin have been extensively applied to restrict the enormous enzyme-catalyzed processes. Hence, the present study was executed to explore the α -amylase inhibition (AAI) potential of glycoprotein isolated from Lactobacillus delbrueckii (LGp) to regulate in vitro starch hydrolysis. As a non-competitive inhibitor, the protein exhibited AAI (85%) with, IC50 135 ± 0.55 μg/mL. It was stable over a broad range of pH (3–11) and temperature (25–75 °C). Furthermore, LGp was significantly effective against amylase and starch from different sources. In addition, it also exhibited antioxidant and emulsifying potential. The UV, FT-IR and fluorescence analysis affirm the alterations in amylase molecular conformation after interaction with the LGp inhibitor. These results provide a substantial basis for the future use of LGp for controlled starch hydrolysis in vitro and as an antioxidant and emulsifying agent in the food industry.